Collision warning and countermeasure systems are becoming more widely used. Collision warning systems are able to detect an object within proximity of a host vehicle and assess whether the object detected is an obstacle and poses a threat to the host vehicle. These systems also provide a vehicle operator with knowledge and awareness of obstacles or vehicles within close proximity in time so that the operator may perform actions to prevent colliding with the detected obstacles. Countermeasure systems exist in various passive and active forms. Some countermeasure systems are used in the prevention of a collision; other countermeasure systems are used in the prevention of an injury to a vehicle operator.
Collision warning systems may be forward or rearward sensing. These systems can indicate to a vehicle operator that an object, which may not be visible to the vehicle operator, is within a stated distance and location relative to the host vehicle. The vehicle operator may then respond accordingly. Other collision warning systems and countermeasure systems activate passive countermeasures such as air bags, load-limiting seat belts, or active vehicle controls including steering control, accelerator control, and brake control whereby the system itself aids in the prevention of a collision or injury.
A detected object of concern may be a real object or a false object. False objects may be detected, for example, when there is a stationary roadside object that is foreseen as a true potentially collision-causing object. A false object may also be detected when a small object, which is not a potential threat, is in the path of the host vehicle and is identified and misclassified as a potentially collision-causing object. Another example situation of when a false object may be generated is when a ghost object is generated, which corresponds with an object that actually does not exist.
The collision warning and countermeasure systems collect data from multiple sensors and associate, fuse, or combine the data to determine whether detected objects are real objects rather than false objects. Advantages of utilizing data from multiple sensors includes extended spatial and temporal coverage, increased accuracy in determining whether an object is a potential threat, and increased reliability in the detection of objects in close proximity of the host vehicle. The stated advantages provide a better assessment of the surroundings of the host vehicle.
There is a current interest in using vision detection sensors, such as cameras, in the detection and classification of objects. Unfortunately, current camera technology requires a large amount of processing power and time to compute relevant information required for in-vehicle use. For example, image processing from a charge coupled device (CCD) camera is time consuming due to the large amount of data collected for each image, approximately 640×480 pixels per frame at 30 frames per second. To accurately classify and track an object can require the acquisition of tens to hundreds of frames of data with each frame having a minimum desired resolution.
Also, template matching is a common technique that has been used in the classification of an object. Template matching typically compares an image region with a set of stored templates for the purpose of determining the identity of an object. Typically, a set of templates is created offline from a set of images of known objects of interest. However, template matching is effective when the set of objects to be recognized is known in advance. Furthermore, it is not practical to generate a complete set of templates for all objects in advance of a potential collision situation, due to the large number of possible combinations of vehicle models, colors, accessories, and payloads. It is further not practical to consider each pixel within an image plane, due to the large computation and time requirements associated therewith.
A desire exists to provide a safer automotive vehicle with increased collision warning and safety countermeasure intelligence to decrease the probability of a collision or of an injury. It is also desireable for a collision warning and countermeasure system to be time efficient and cost effective. Thus, there exists a need for an improved cost effective collision warning and safety countermeasure system that utilizes time and system resource efficient object detection and classification techniques.